How can I randomize a video to play after another by pressing a key on Processing?

Question

I'm quite new to Processing.

I'm trying to make Processing randomly play a video after I clear the screen by mouseclick, so I create an array that contain 3 videos and play one at a time.

Holding 'Spacebar' will play a video and release it will stop the video. Mouseclick will clear the screen to an image. The question is how can it randomize to another video if I press spacebar again after clear the screen.

I've been searching all over the internet but couldn't find any solution for my coding or if my logic is wrong, please help me.

Here's my code.

int value = 0;
PImage photo;
import processing.video.*;

int n = 3; //number of videos

float vidN = random(0, n+1);
int x = int (vidN);

Movie[] video = new Movie[3];
//int rand = 0;

int index = 0;

void setup() {
  size(800, 500);
  frameRate(30);
  
  video = new Movie[3];
  video[0] = new Movie (this, "01.mp4");
  video[1] = new Movie (this, "02.mp4");
  video[2] = new Movie (this, "03.mp4");

  photo = loadImage("1.jpg");
}

void draw() {
}

void movieEvent(Movie video) {
  video.read();
}

void keyPressed() {

  if (key == ' ') {
    image(video[x], 0, 0);
    video[x].play();
  }
}

void mouseClicked() {
  if (value == 0) {
    video[x].jump(0);
    video[x].stop();
    background(0);
    image(photo, 0, 0);
  }
}

Answer 1

You have this bit of logic in your code which picks a random integer:

float vidN = random(0, n+1);
int x = int (vidN);

In theory, if you want to randomise to another video when the spacebar is pressed again you can re-use this bit of logic:

void keyPressed() {

  if (key == ' ') {
    x = int(random(n+1));
    image(video[x], 0, 0);
    video[x].play();
  }
  
}

(Above I've used shorthand of the two lines declaring vidN and x, but the logic is the same. If the logic is harder to follow since two operations on the same line (picking a random float between 0,n+1 and rounding down to an integer value), feel free to expand back to two lines: readability is more important).

As side notes, these bit of logic look a bit off:

1. the if (value == 0) condition will always be true since value never changes, making both value and the condition redundant. (Perhaps you plan to use for something else later ? If so, you could save separate sketches, but start with the simplest version and exclude anything you don't need, otherwise, in general, remove any bit of code you don't need. It will be easier to read, follow and change.)
2. Currently your logic says that whenever you click current video resets to the start and stops playing and when you hit the spacebar. Once you add the logic to randomise the video that the most recent frame of the current video (just randomised) will display (image(video[x], 0, 0);), then that video will play. Unless you click to stop the current video, previously started videos (via play()) will play in the background (e.g. if they have audio you'll hear them in the background even if you only see one static frame from the last time space was pressed).

Maybe this is the behaviour you want ? You've explained a localised section of what you want to achieve, but not overall what the whole of the program you posted should do. That would help others provide suggestions regarding logic.

In general, try to break the problem down to simple steps that you can test in isolation. Once you've found a solid solution for each part, you can add each part into a main sketch one at a time, testing each time you add something. (This way if something goes wrong it's easy to isolate/fix). Kevin Workman's How To Program is a great article on this.

As a mental excercise it will help to read through the code line by line and imagine what it might do. Then run it and see if the code behaves as you predicted/intended. Slowly and surely this will get better and better. Have fun learning!